Comments:  The male Yellow Warbler has rusty breast streaks.  Compare the Yellow Warbler to the Common Yellowthroat with a black streak through the eye and to the Yellow Hooded Warbler sporting a black hood.  The American Goldfinch is similar in color with a black wing.  The Yellow Warbler and the Prairie Warbler sometimes look like yellow sparrows due to the streaking on their breasts. 

Bent:  "Voice.--Aretas A. Saunders contributes the following study of the song of this warbler: "The song of the yellow warbler is a bright, sweet and musical refrain of about 8 notes. My records show that the number varies from 5 to 15 and averages 8 1/2. The songs are quite variable in form, so much so that it is the quality, rather than the form, that makes the song recognizable. This quality is difficult to describe, yet that quality, after a little familiarity, is easily recognized; the tones though musical and pleasing, are not quite clear, but slightly sibilant. "Two forms of the song are fairly typical, but there are a number of others that vary so much that they are quite unlike either of these. The most common form begins with four or five notes of even time, and all on the same pitch. These are followed by two or three more rapid notes on a different pitch, usually lower; and the song is ended by one or two notes back on the original pitch and time. Such a song, in its simplest form, might be written see see see see tititi see. Of my 87 records, 45 may be classed as this form. "The second form begins in the same manner, but has all the notes of equal time, the last three or four successively lower in pitch. I have records of 24 such songs. There remain in my records 18 songs so variable that they belong to neither of these forms, and yet no two of them are similar in form. A number of songs of the different forms begin with slurred notes, the slurs being about equally up or down in pitch.  "Songs vary from 1 1/5 to 2 seconds in length, averaging about 1 2/5 seconds. The pitch varies from A'''' to D''''', only three and a half tones altogether. Single songs vary from one to two and a half tones in range of pitch, averaging about one and a half tones. Individual birds may sing as many as three different songs, and sometimes sing two different songs in regular alternation. "Singing continues from the first arrival in migration until the third week of July, ceases for a short time, but is usually revived in August, and is to be heard irregularly until the birds depart for the south."  

Francis H. Allen gives me his impressions of the two common songs as follows: "One of these I have been accustomed to render as wee see wee see wiss wiss'-u. Occasionally the final wiss'-u is doubled. The other of these two songs goes something like wee wee wee witita weet, without the drop in the pitch that the first song has at the final note. I have also heard a song of five single notes with no variation in pitch or tempo--weet weet weet weet weet. Besides a rather sharp chip, which is the ordinary call-note, I have heard a dzee from a yellow warbler." The yellow warbler is an early riser. Mr. Smith (1943) heard one begin singing at 4:56 a.m., "daylight time," and another at 4:05, "but with only one song until 4:08 when seven were given during the space of one minute. During the song period of fifty minutes 197 songs were given." Dr. Charles W. Townsend told Mr. Allen that he heard one at Ipswich, Mass., on June 13, 1908, that began singing at 3:10 a.m., but this was standard time. 

Dr. Winsor M. Tyler (1937) mentions a peculiar note, heard during the migration in August, which had puzzled him for nearly 30 years until he finally traced it to an eastern yellow warbler. 'As we walk under the trees, listening, we hear a long, wild, high, sharp bird-note, abrupt, and very slightly vibratory, lasting perhaps half a second. It is a characteristic sound of this time of year, and we hear it best on these quiet, silent days. It comes from a bird moving restlessly up in the trees, and before we can see the bird, it is gone. . . . In pitch, it suggests the call of a migrating Ovenbird, but it is too long-drawn-out; it suggests the chip of a Northern Water-Thrush in its sharp abruptness, but again it is too long.' 

According to Albert R. Brand (1938) there is considerable variation in the pitch of the song of the eastern yellow warbler, from 8,775 vibrations per second in the highest note to 3,475 in the lowest note, and with an approximate mean of 5,900 vibrations per second. This is far below the approximate mean of 8,900 for the black-poll warbler, but well above the average of 4,000 for all passerine birds."  Bent, Life Histories of North American Birds, 

Stokes:  'Song sounds like "sweet, sweet, sweet, I'm so sweet", with last note accented.  Also has unaccented song version.  Call is a musical "chip".'

Robbins:  "Song has about 7 clear sweet notes, second half slightly faster, typically with the final note slurred upward, 4-10/min.

Peterson: A cheerful bright "tsee-tsee-tsee-tsee-ti-ti-wee" or "weet weet weet weet tsee tsee".

Bittner:  Other song patterns include, "Ta-weet, tweet, practice my tweets"

Delaware Water Gap:  This bird is abundant in the tall brush between Old Mine Road and the Delaware at the Coppermines Trail Parking Area; also around Catfish Pond and the brush near the Interpretive Center of the Mohican Outdoor Center.